Silicon (Si) is conventionally widely adopted as a substrate (interposer) required when forming a semiconductor device.
However, since silicon (Si) is an expensive material, technology of using an inexpensive glass substrate in place of this is suggested.
However, since several glass substrates of approximately 0.3 to 0.5 mm are stacked when the glass substrate is used, a transmission loss might occur.
Technology of forming a coaxial structure or a microstrip line structure with a drill when an organic substrate is used is suggested as a countermeasure against the transmission loss (refer to Patent Documents 1 and 2).
Also, technology of collectively forming the microstrip line structure by Deep RIE when a silicon substrate is used is suggested as a similar countermeasure (refer to Patent Document 3).